The present invention relates in general to apparatus for handling electric audio signals for producing controlled distortion in the audio output signals and for enhancing the tonal quality thereof. More particularly, the present invention is directed to an improved compressor circuit which from a general standpoint, compresses the intensity range of the output signal therefrom as compared to the range of the input signal thereto.
Accordingly, an object of the present invention is to provide an improved electronic audio signal processor particularly having improved tonal quality of the audio signal.
A further object of the present invention is to provide an improved compressor circuit which forms a part of the electronic audio signal processor and which is characterized by lower noise operation particularly in the distortion mode of operation.
Still another object of the present invention is to provide an improved compressor circuit which is characterized by high end boost or enhancement, particularly at low volume operation.
Another object of the present invention is to provide an improved compressor circuit in accordance with the preceding objects and is characterized by improved weak note recovery operation.
To accomplish the foregoing and other objects of this invention, there is provided in an electronic audio signal processor, an improved signal compressor circuit for receiving the output from a high pass audio filter and for producing an output signal having increased low audio and high audio signal content relative to the middle audio signal content. In particular, the circuit of the present invention is characterized by lower noise, particularly in the distortion mode of operation, is also characterized by a high end boost at low volume and by better weak note recovery. In the disclosed embodiment of the invention the compressor circuit comprises an operational amplifier having associated therewith in a feedback loop, an FET transistor with the output of the FET transistor coupled back to the operational amplifier by a unique circuit in the form of an RC circuit that provides the aforementioned improved operation.